<?php
$a_latitude = 0.1774;  //a点纬度
$a_longitude = 1; //a点经度
$b_latitude = 55;
$b_longitude = 1;

$distance =   sin(deg2rad($a_latitude))
            * sin(deg2rad($b_latitude))
            + cos(deg2rad($a_latitude))
            * cos(deg2rad($b_latitude))
            * cos(deg2rad($a_longitude - $b_longitude));
$distance = (rad2deg(acos($distance))) * 69.09;


var_dump($distance);